When comparing this type of comment to
the basic HTML Comment, notice that
there are no hyphens ("--")
immediately after the opening "" of
the comment block; therefore, the
comment delimiters are treated as
unrecognized HTML. Because the browser
does not recognize the
downlevel-revealed conditional
comment, it does nothing with it.

3 Answers
3

There's two different cases. For <![if lt IE 8]>, this is processed in non IE browsers as a "bogus comment" and results in a comment node being added to the DOM. For what IE does, see Axel Fontaine's answer.

For <video ...> browsers other than IE (version 8 or earlier) will create a element in the DOM called "video" and it's contents will be children of the "video" element. IE, if the HTML5 shiv is used, will do the same thing.

For IE prior to IE9, without the HTML5 shiv, the <video ...> tag will cause one element called "VIDEO" will be created. It will be empty. The embed and any other contents will be siblings of it. Then the </video> tag will cause another element to be added to the DOM called "/VIDEO"

As a side issue, the <embed> element is void, so </embed> is never correct. Adding it causes an element called "/EMBED" to be added to the DOM in IE versions prior to IE9.

It's just an IE thing. Other browsers will recognise <![if lt IE 8]> and the other one as tags, and so ignore them. They won't ignore the content between them though, so all browsers except IE 8 will show the paragraph, so I would advise against using this format. Instead, work on making your pages degrade gracefully.

you are right. sorry i just mis interpreted the text and miss understood the concept. the whole point of this syntax is do show it if the tag is not recognised and hidden.
–
The SurricanJan 27 '11 at 19:55